Effects of temperature and hypoxic stress on the oxygen consumption rates of the mudsucker fish Labeo capensis (Smith)

Abstract

The specific oxygen consumption rate (VO₂lMb) of Labeo capensis, the freshwater mudsucker, was determined for small and large fish at winter (8°C) and summer (23°C) temperatures. VO₂lMb was also determined during hypoxic conditions of the experimental water. It was found that VO₂lMb does not differ substantially compared with other active fish. The VO₂lMb for a fish with a body mass of 250 g is 0,053 ml 0₂ per gram wet body mass per hour for fish acclimated at 8°C and 0,127 ml 0₂ per gram per hour for fish acclimated at 23°C. The calculated mass exponent, b, is 0,71 at 23°C and 0,68 at 8°C. Hypoxic conditions are relatively well tolerated especially by 23°C- adapted fish.